> because of programs like the city's recent ban on plastic shopping bags, efforts to promote solar energy, and the city's comprehensive composting program, this year san francisco was named earth hour city capitol for the u.s. i talked to the earth hour ceo by skype from singapore. >> managers would say, save money by cut you're usi power you're using and make your city a better place to live in, which is what san francisco has done. reporter: and san francisco joined other cities around the world with lights out. at 8:30 local time in sidney, australia, they darkened the bridge, and the house of parliament in london went out. the switching the lights off for an hour are to encourage the public. >> we hoped people would think about earth hour, hour by hour, every day. >> ama: o problems of achieving a clean environment is underscored by a new united nations study. incredibly, the study found more people around the world have access to cell phones than to a working toilet. u.s. officials say this goes to the heart of human dignity for billions of people. >> if you plan on buying an ipad, m